~ This is what I am and what I do.. !!

Category Archives: Networking

After a fresh installation of CentOS in a new machine, the OS can not automatically connect to the network by default. So, the user/admin should manually change few setting so that the new system can gain a new IP address and connect to the internet.

To start, type nmcli d to check if the NIC card is installed properly.

Now the nmtui will open up the network manager setting for the centOS.

Choose the Edit a connection option

Choose the network interface and activate

Now, Click edit to configure the network settings

Check on the automatically connect option and OK to exit from network manager

Restart the network services

Enter the password of the root to commit the changes

Use the command IP a to see the IP configuration detail of the interfaces.

"xp_cmdshell" is an extended stored procedure provided by Microsoft and stored in the master database. This procedure allows you to issue operating system commands directly to the Windows command shell via T-SQL code.

Let’s start out with a simple directory search example. Say you do not have access to the physical SQL Server machine, but you want to see all the files are accessible form the database service. To do that enter the below command with the original path of the share path

Five areas comprise the memory of Cisco devices. These memory areas are used to store static and dynamic device configuration data. These memory areas are as follows:

✦ Read-Only Memory (ROM): The ROM stores programs and data necessary to start up the Cisco device. This memory keeps its contents even when the Cisco device is powered down. ROM is kept on EPROM (erasable programmable read-only memory) chips.

✦ Flash Memory: The flash memory stores the Cisco IOS. Flash memory keeps its contents even when the Cisco device is powered down. Flash memory is kept on EEPROM chips, on PCMCIA cards, or on CompactFlash cards. The PCMCIA and CompactFlash cards can be accessed either internally on the Cisco device motherboard or externally through a PCMCIA or CompactFlash external slot.

✦ Nonvolatile Random-Access Memory (NVRAM): The NVRAM stores the startup configuration. This is the configuration that Cisco IOS loads when it boots up. NVRAM keeps its contents even when the Cisco device is powered down.

✦ Random-Access Memory (RAM): The RAM stores the running configuration. This is the dynamic data that changes while the Cisco device is in normal operation mode. This includes the Address Resolution Protocol (ARP) cache (MAC address tables), routing tables, STP data, VLAN data, Ether Channel configuration data, and temporary buffers. RAM does not keep its contents when the Cisco device is powered down. Upon startup, RAM is initialized with contents from NVRAM.

✦ Configuration Register: The configuration register is a 2-byte (16-bit) area of NVRAM that holds a numeric value that defines how the Cisco device starts up. By default, the value stored in the configuration register instructs the bootstrap program to load the Cisco IOS from flash memory and to load the startup configuration from NVRAM. You can change the value of the configuration register from the ROMMON prompt. To get to the rommon> prompt, you need to break out of the bootstrap process by pressing Ctrl+Break while the Cisco device is booting up.

The simplest and the most widespread classful distance vector routing protocol is the Routing Information Protocol (version 1). RIP uses hop count as its metric for path selection. Hop counts greater than 15 are marked as unreachable and broadcast messages every 30 seconds. RIP being classful does not send subnet mask in its update. Default administrative distance is 120. RIP Version 1 does not support classless (discontiguous) networks or VLSM instead RIP Version 2 support these

Netflow is a cisco IOS application which can collect information of IP traffic. Netflow can maintain detailed log of network resources. It can measure who is using which resources for which purpose Based on the usage of NetFlow analyzers, you will be able to identify the following: – The major users of the network – The websites that are routinely visited and what is downloaded – Who is generating the most traffic – If you have enough bandwidth to support mission-critical activity – Who is using excessive bandwidth